Article
Precipitation Intensification Increases Shrub Dominance in Arid, Not Mesic, Ecosystems
Ecosystems
(2022)
Abstract
Precipitation events have been predicted and observed to become fewer, but larger, as the atmosphere warms. Water-limited ecosystems are especially sensitive to changes in water cycling, yet evidence suggests that productivity may either increase or decrease in response to precipitation intensification. Interactions among climate, soil properties, and vegetation type may explain different responses, but this is difficult to experimentally test over large spatial scales. Simulation modeling may reveal the mechanisms through which climate, soils, and vegetation interact to affect plant growth. We use an individual-based plant ecohydrological model to simulate the effects of 25%, 50%, and 100% increases in precipitation event sizes on water cycling and shrub, grass, and forb biomass in 200 shrub-steppe sites spanning 651,000 km2 of the Intermountain West, USA. Simulations did not change annual precipitation amounts and were performed for 0, 3, and 5 °C warming. Larger precipitation events decreased evaporation and ‘pushed’ water into shrub root zones in arid and semi-arid sites, but ‘pushed’ water below shrub root zones in mesic sites resulting in increased shrub biomass in arid and semi-arid, but not mesic, sites. Positive effects of precipitation intensification on shrub growth partially counteracted negative effects of warming. Grasses and forbs showed no consistent response to precipitation intensification. Results indicate that increased precipitation intensity creates a competitive advantage for shrubs in arid and semi-arid sites. This advantage results in greater shrub relative abundance and suggests that precipitation intensification contributes to woody plant encroachment observed globally in arid and semi-arid ecosystems.
Disciplines
Publication Date
2022
DOI
https://doi.org/10.1007/s10021-022-00778-1
Citation Information
Karen H. Beard. "Precipitation Intensification Increases Shrub Dominance in Arid, Not Mesic, Ecosystems" Ecosystems (2022) Available at: http://works.bepress.com/karenh_beard/397/